1. Field of the Invention
The present invention relates to a data input system for inputting data to a database.
2. Summary of the Prior Art
It is now becoming increasingly common for an operating system, such as in industrial plant, to be operated on the basis of an "expert system" which operates on the basis of data stored in a database. It is generally accepted that a database used in an expert system is part of a "growing system", because the data is constantly being increased or changed, by actual operation of the system by the user, so that no final completion is ever achieved.
In such a system, the data represents relationships, and in this specification the term data (or information) refers to an operating relationship between operating parameters of the operating system. Those parameters may be operating conditions, process variables, or fixed values.
Some of that data may be initially input to the system (stored in the database) by the manufacturer of the system and therefore the validity of the data may be determined before the system is in operation. However, when the system is in operation, further data must be manually entered into the database by an operator and it is therefore necessary to ensure the integrety and validity of such data. Furthermore, differences may develop between the data initially stored in the database and the data that is actually used after, perhaps, years of operation of the system. These factors can result in invalid data within the system, which is to be avoided.
When considering these two factors, various arrangements have been proposed to try to overcome them. In Japanese Patent Application No. 60-41128, the data input by several operators is first passed to a database administrator, who is trained to determine which data can be stored in the database. This system, of course, requires that the database administrator be fully aware of the correct operating relationships, and the level of training needed for this is a limit to the practicality of this proposal.
The problem of the development of invalid data over a period of time was considered by Japanese Patent Application No. 58-192161, in which "age" information is associated with the data being input, and the data is automatically deleted after expiration of a predetermined age limit. This is also not a satisfactory solution, since valid data, which may subsequently be useful, will be deleted if it has reached its age limit.
Thus, neither of these two proposals adequately face the problem of input of invalid data, and this provides a limit to the practicality of the use of databases in such expert systems.